Exposure method, exposure apparatus, and device manufacturing method

ABSTRACT

A liquid immersion device that has an mixing mechanism that mixes and dissolves a predetermined substance for adjusting specific resistance of the liquid, which is supplied onto a liquid repellent film on the surface of an object (member) of a projection optical system placed on the light emitting side of projection optical system, and an liquid immersion area is formed by supplying the liquid in which the predetermined liquid is dissolved onto the liquid repellent film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of prior pending application Ser. No.11/640,842, filed Dec. 19, 2006, which in turn is a Continuation ofInternational Application PCT/JP2006/308385, with an internationalfiling date of Apr. 21, 2006, the disclosures of which are herebyincorporated herein by reference in their entirety. This non-provisionalapplication also claims the benefit of Provisional Application No.60/751,208 filed Dec. 19, 2005, the disclosure of which is herebyincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to exposure methods, exposure apparatus,and device manufacturing methods, and more particularly to an exposuremethod and an exposure apparatus that are used when exposing an objectvia a liquid, and a device manufacturing method that uses the exposuremethod and the exposure apparatus in a lithographic process.

2. Description of the Background Art

Conventionally, in a lithographic process to produce electronic devicessuch as a semiconductor (integrated circuit) or a liquid crystal displaydevice, the reduction projection exposure apparatus based on astep-and-repeat method (the so-called stepper) that transfers an imageof a pattern of a mask (or a reticle) via a projection optical systemonto each of a plurality of shot areas on a sensitive object such as awafer, a glass plate or the like (hereinafter generally referred to as a“wafer”), on which a resist (sensitive agent) is coated, the projectionexposure apparatus based on a step-and-scan method by (the so-calledscanning stepper (also called a scanner) and the like are mainly used.

With these types of projection exposure apparatus, a higher resolvingpower (resolution) is required year by year due to finer patternsaccording to higher integration of the integrated circuits, and inrecent years, as a method for substantially shortening the exposurewavelength and also increasing (widening) the depth of focus comparedwith the depth of focus in the air, exposure apparatus that use theliquid immersion method are beginning to gather attention. As anexposure apparatus that uses the liquid immersion method, an exposureapparatus that performs exposure in a state where the space between thelower surface of a projection optical system and the surface of a waferis filled with liquid such as water, an organic solvent or the like isknown (e.g. refer to the pamphlet of International PublicationWO99/49504 description). In the exposure apparatus according to PatentDocument 1, the resolution is improved by the use of the fact that thewavelength of the exposure light in the liquid becomes 1/n of thewavelength in the air (n is the refractive index of the liquid which isnormally around 1.2 to 1.6), and the depth of focus is alsosubstantially enlarged n times when comparing it with the case when thesame resolution is obtained without applying the liquid immersion methodto the projection optical system (supposing that such a projectionoptical system can be made). That is, the depth of focus can besubstantially enlarged n times than in the air.

However, in the liquid immersion exposure apparatus described earlier,various measurements related to exposure are performed in a state wherean liquid immersion area is formed on an object (a member) on which theexposure light is irradiated.

Further, in the liquid immersion exposure apparatus, pure water orpurified water is proposed as an example of the liquid. This is becausepurified water can be obtained in large quantities at a semiconductormanufacturing plant or the like, and it also has an advantage of havingno adverse effect on the photoresist on the wafer or to the opticallenses or the like.

However, because purified water has high specific resistance, staticelectricity is generated due to friction with piping, nozzles or thelike, and in the case the liquid immersion area is formed on the object(the member) with the charged purified water, there is a possibilitythat the object (the member) or a film on the surface of the object (themember) or both may be electrically charged. In this case, the film onthe surface of the object (the member) on which the liquid immersionarea is formed could be deteriorated or damaged. The deterioration ofthe film may cause unevenness in the optical properties of thedeteriorated section and the section besides the deteriorated section,and/or may be the cause of water stains (water marks), which mayconsequently decrease the exposure accuracy. Further, foreign substancesor foreign matters may adhere on the surface of the object (the member)by the charge, and such foreign substances may contaminate the liquid(purified water), the wafer and the like, which may cause faultyexposure such as defects.

Further, in the case the liquid immersion area is formed on the object(e.g. a wafer) subject to exposure with the charged purified water, thefilm (a resist layer, and/or a top coat layer) on the object (the wafer)could be charged. In this case, deterioration, modification or the likemay occur on the film (a resist layer, and/or a top coat layer) on theobject (the wafer), which could be the cause of defects being generated.

Further, in the case the object (the wafer) subject to exposure ischarged, foreign substances may be adhered on the surface of the object(the wafer), and the liquid (purified water) and the object (the wafer)subject to exposure may be contaminated, which may cause faulty exposuresuch as defects.

SUMMARY OF THE INVENTION

The present invention was made under such circumstances, and accordingto a first aspect of the present invention, there is provided anexposure method in which an object is exposed via a liquid, the methodcomprising: a process in which a predetermined substance that adjustsspecific resistance of the liquid is dissolved in the liquid and anliquid immersion area is formed by supplying the liquid in which thepredetermined substance is dissolved on a film formed on the object; anda process in which exposure is performed by irradiating an exposurelight on the object via the liquid and a predetermined pattern isformed.

According to this method, by dissolving the predetermined substance andreducing the specific resistance of the liquid, the liquid immersionarea can be formed on the film formed on the object with the liquidwhose specific resistance is reduced. Therefore, the charge of theliquid is prevented or effectively suppressed, and generation ofdielectric breakdown of the film on the object where the liquidimmersion area is formed can be effectively suppressed. Accordingly, byperforming the exposure in which the exposure light is irradiated on theobject via the liquid of which the charge is prevented or effectivelysuppressed and a predetermined pattern is formed, the pattern can beformed on the object with good precision for over a long period of time.

According to a second aspect of the present invention, there is provideda first exposure apparatus that exposes an object by irradiating anexposure beam on the object via an optical member and a liquid and formsa predetermined pattern on the object, the apparatus comprising: asensor that receives a light that has the same wavelength as theexposure beam via a liquid repellent film on the surface of a memberplaced on the light emitting side of the optical member and a liquid onthe liquid repellent film; and a liquid immersion device that has amixing mechanism in which a predetermined substance that adjustsspecific resistance of the liquid supplied onto the liquid repellentfilm is mixed and dissolved in the liquid, and supplies the liquid inwhich the predetermined substance is dissolved onto the liquid repellentfilm so as to form an liquid immersion area.

According to this apparatus, the liquid immersion device has the mixingmechanism that mixes and dissolves the predetermined substance foradjusting specific resistance of the liquid, which is supplied onto theliquid repellent film on the surface of the member placed on the lightemitting side of the optical member, and the liquid immersion area isformed by supplying the liquid in which the predetermined liquid isdissolved onto the liquid repellent film. Therefore, the specificresistance of the liquid can be reduced so that the charge of the liquidis prevented or effectively suppressed, and generation of dielectricbreakdown of the liquid repellent film where the liquid immersion areais formed can be effectively suppressed. Accordingly, measurement withhigh precision can be executed by the sensor for over a long period oftime, and by performing the exposure in which the exposure beam isirradiated on the object via the liquid with the measurement resultsbeing reflected, exposure with high precision can be performed for overa long period of time.

According to a third aspect of the present invention, there is provideda second exposure apparatus that exposes an object by irradiating anexposure beam on the object via a liquid and forms a predeterminedpattern on the object, the apparatus comprising: an object stage onwhich the object is mounted; and a liquid immersion device that has amixing mechanism in which a predetermined substance that adjustsspecific resistance of the liquid supplied onto a predetermined filmformed on the object mounted on the object stage is mixed and dissolvedin the liquid, and supplies the liquid in which the predeterminedsubstance is dissolved onto the film so as to form an liquid immersionarea.

According to this apparatus, the liquid immersion device has a mixingmechanism that mixes and dissolves, in the liquid to be supplied ontothe predetermined film formed on the object mounted on the object stage,a predetermined substance for adjusting specific resistance of theliquid, and the liquid immersion device forms the liquid immersion areaon the film on the object with the liquid in which the predeterminedliquid is dissolved. Therefore, with the liquid whose specificresistance has been reduced, the liquid immersion area is formed on thefilm formed on the object. As a consequence, the charge of the liquid isprevented or effectively suppressed, and generation of dielectricbreakdown of the film member on the object where the liquid immersionarea is formed can be effectively suppressed. Accordingly, by performingthe exposure in which the exposure beam is irradiated on the object viathe liquid whose charge is prevented or effectively suppressed so as toform a predetermined pattern, the pattern can be formed on the objectwith good precision.

Further, in a lithographic process, by using the exposure method of thepresent invention, a pattern can be formed with good accuracy on anobject. Therefore, according to a fourth aspect of the presentinvention, it can also be said that the present invention is a devicemanufacturing method including a lithographic process in which a devicepattern is formed on the object using the exposure method of the presentinvention. Further, by using one of the first and second exposureapparatus of the present invention in the lithographic process, apattern can be formed on an object with good precision. Therefore,according to a fifth aspect of the present invention, it can also besaid that the present invention is a device manufacturing methodincluding a lithographic process in which a device pattern is formed onthe object using one of the first and second exposure apparatus of thepresent invention.

According to a sixth aspect of the present invention, there is provideda device manufacturing method including a lithographic process in whichan object is exposed via a liquid within an exposure apparatusconnecting to a substrate processing unit and a device pattern is formedon the object, wherein electrical charge of the object is removed bysoaking the object in a conductive liquid before the object is carriedinto the exposure apparatus.

According to this method, because electrical charge of the object isremoved before the object is carried into the exposure apparatus,adherence of foreign substances can be suppressed, which can preventexposure defects of the object.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings;

FIG. 1 is a schematic view of an arrangement of an exposure apparatusrelated to an embodiment;

FIG. 2 is a planar view of a stage unit in FIG. 1;

FIG. 3 is a schematic view of a liquid supply unit;

FIG. 4 is a planar view of a measurement table;

FIG. 5 is a longitudinal sectional view of a measurement table showingthe vicinity of an illuminance monitor 122; and

FIG. 6 is a block diagram for showing a main arrangement of a controlsystem of an exposure apparatus related to an embodiment.

DESCRIPTION OF THE EMBODIMENTS

An embodiment of the present invention is described below, referring toFIGS. 1 to 6.

FIG. 1 is an entire view of an arrangement of an exposure apparatus 100related to the embodiment. Exposure apparatus 100 is a scanning exposureapparatus based on a step-and-scan method, that is, the so-calledscanner.

Exposure apparatus 100 is provided with an illumination system ILS, areticle stage RST that holds a reticle R serving as a mask illuminatedby an exposure illumination light IL serving as an energy beam fromillumination system ILS and moves in a predetermined scanning direction(in this case, a Y-axis direction which is the lateral direction of thepage surface in FIG. 1), a projection unit PU including a projectionoptical system PL that projects exposure illumination light IL emittedfrom reticle R onto a wafer W, a stage unit 150 including a measurementstage MST used on measurement for exposure, a control system of theseparts, and the like.

As the light source installed in illumination system ILS, as an example,an ArF excimer laser light source (output wavelength: 193 nm) is used,which is a pulsed light source that generates light in the vacuumultraviolet region with the wavelength of 200 nm to 170 nm.

Further, illumination system ILS includes a beam shaping optical system,a rough energy adjuster, an optical integrator (a uniformizer, or ahomogenizer), an illumination system aperture stop plate, a beamsplitter, a relay lens, a reticle blind, a mirror for bending theoptical path, a condenser (none of which are shown) and the like, whichare placed in a predetermined positional relation. Details on thearrangement of illumination system ILS and the function of each opticalmember are disclosed in, for example, the pamphlet of InternationalPublication WO2002/103766, and the like.

On reticle stage RST, reticle R on which a circuit pattern or the likeis formed on the pattern surface (the lower surface in FIG. 1) is fixed,for example, by vacuum suction. Reticle stage RST can be finely drivenin an XY plane by a reticle stage drive system 55 that includes, forexample, a linear motor and the like, and can also be driven at adesignated scanning speed in a predetermined scanning direction (in thiscase, the Y-axis direction, which is the lateral direction of the pagesurface of FIG. 1).

The position of reticle stage RST within the stage movement plane(including rotation around a Z-axis) is constantly detected by a reticlelaser interferometer (hereinafter referred to as “reticleinterferometer”) 53 via a movable mirror 65 (a Y movable mirror that hasa reflection surface orthogonal to the Y-axis direction and an X movablemirror that has a reflection surface orthogonal to an X-axis directionare actually arranged) at a resolution of, for example, around 0.5 to 1nm. The measurement values of reticle interferometer 53 is sent to amain controller 50, and based on the measurement values of reticleinterferometer 53, main controller 50 controls the position (andvelocity) of reticle stage RST in the X-axis direction, the Y-axisdirection, and a θz direction (a rotation direction around the Z-axis)via stage reticle drive system 55.

Above reticle R, a pair of reticle alignment detection systems RAa andRAb are arranged in the X-axis direction at a predetermined distance,each consisting of a TTR (Through The Reticle) alignment system thatuses light of the exposure wavelength to observe a pair of reticle markson reticle R and a corresponding pair of fiducial marks (hereinafterreferred to as “a first fiducial mark”) on a fiducial mark plate FM(refer to FIG. 2) arranged on measurement stage MST, at the same timevia projection optical system PL. As such reticle alignment detectionsystems RAa and RAb, a system having a structure similar to the onedisclosed in, for example, Kokai (Japanese Unexamined Patent ApplicationPublication) No. 7-176468 and the corresponding U.S. Pat. No. 5,646,413or the like is used. As long as the national laws in designated states(or elected states), to which this international application is applied,permit, the above disclosures of the Kokai publication and the U.S.patent are incorporated herein by reference.

Projection unit PU is arranged below reticle stage RST in FIG. 1.Projection unit PU is configured including a barrel 140, and projectionoptical system PL consisting of a plurality of optical elements held ina predetermined positional relation within barrel 140. As projectionoptical system PL, a dioptric system is used, consisting of a pluralityof lenses (lens elements) that share an optical axis AX in the Z-axisdirection. Projection optical system PL is, for example, a both-sidetelecentric dioptric system and has a predetermined projectionmagnification (such as one-quarter, one-fifth, or one-eighth times).Therefore, when illumination light IL from an illumination opticalsystem 12 illuminates an illumination area IAR on reticle R, a reducedimage of the circuit pattern within illumination area IAR of reticle R(a partial reduced image of the circuit pattern) is formed on the waferof which surface is coated with a resist (a sensitive agent) in an areaconjugate with illumination area IAR (hereinafter also referred to as an“exposure area”) by illumination light IL that has passed throughreticle R, via projection optical system PL (projection unit PU). In theembodiment, an end optical element 191 that constitutes projectionoptical system PL closest to the image plane side (the wafer side) is alens that has refractive power, however, end optical element 191 mayalso be a parallel plane plate.

Further, out of a plurality of lenses constituting projection opticalsystem PL, a specific plurality of lenses operates under the control ofan image forming characteristics correction controller 52 based oncommands from main controller 50, and the optical properties (includingimage-forming characteristics) of projection optical system PL such as,for example, magnification, distortion, coma, curvature of image plane(including inclination of image plane) or the like, can be adjusted.

In exposure apparatus 100 of the embodiment, an exposure, to which theliquid immersion method is applied, is performed as in the descriptionlater on, and thus the numerical aperture NA substantially increaseswhich makes the opening on the reticle side larger. Therefore, in adioptric system consisting only of lenses, it becomes difficult tosatisfy the Petzval condition, which tends to lead to an increase in thesize of the projection optical system. In order to prevent such anincrease in the size of the projection optical system, a catodioptricsystem that includes mirrors and lenses may also be used.

Further, in exposure apparatus 100 of the embodiment, in the vicinity oflens 191, which serves as an end optical element (hereinafter alsoreferred to as a “tip lens”) that constitutes projection optical systemPL closest to the image plane side (the wafer W side), a liquid supplynozzle 131A and a liquid recovery nozzle 131B that constitute a part ofan liquid immersion unit 132 are arranged.

Liquid supply nozzle 131A connects to the other end of a supply pipe 78(not shown in FIGS. 1 and 6, refer to FIG. 3) that has one end connectedto a part of a liquid supply unit 138 (not shown in FIG. 1, refer toFIG. 6), and liquid recovery nozzle 131B connects to the other end of arecovery pipe (not shown) that has one end connected to a liquidrecovery unit 139 (not shown in FIG. 1, refer to FIG. 6).

In the embodiment, a liquid Lq used for liquid immersion (refer toFIG. 1) is to be made using pure water or purified water that transmitsthe ArF excimer laser beam (light with a wavelength of 193 nm). Purewater can be obtained in large quantities at a semiconductormanufacturing plant or the like, and it also has an advantage of havingno adverse effect on the photoresist on the wafer, the optical lenses orthe like.

FIG. 3 shows an example of a configuration of liquid supply unit 138. Asis shown in FIG. 3, liquid supply unit 138 is provided with a pure watersupply pipe 84 that has one end connected to a factory piping for purewater of the semiconductor manufacturing plant and the other endconnected to one end of a CO₂ dissolving tank 82 that also functions astank for the liquid, a flow control electromagnetic valve 86A arrangedalong pure water supply pipe 84, a CO₂ supply pipe 88 that connects oneend of CO₂ dissolving tank 82 described above and a CO₂ tank (notshown), a flow control electromagnetic valve 86B arranged along CO₂supply pipe 88, a supply piping 90 that has one end connecting to theother end of CO₂ dissolving tank 82 (on the opposite side of pure watersupply pipe 84), a liquid temperature adjustment unit 72 that has oneend connected to the other end of supply piping 90 and performstemperature adjustment of the liquid, a pressurized pump 74 and aspecific resistance indicator 76 arranged along supply piping 90, asupply pipe 78 that has one end connected to the other end of liquidtemperature adjustment unit 72 and liquid supply nozzle 131A arranged inthe other end, a controller 80 connecting to sections such as liquidtemperature adjustment unit 72, flow control electromagnetic valves 86Aand 86B, pressurized pump 74, specific resistance indicator 76 and thelike.

Controller 80 makes pressurized pump 74 operate under instructions frommain controller 50, and during the operation, controller 80 alsocontrols flow control electromagnetic valves 86A and 86B whilemonitoring specific resistance values of the liquid from CO₂ dissolvingtank 82 (pure water in which carbon dioxide is dissolved) measured byspecific resistance indicator 76, so that the specific resistance valuesmeasured become values within a predetermined range. Accordingly, withinCO₂ dissolving tank 82, carbon dioxide (CO₂) supplied from a CO₂ tankbecomes mixed or incorporated into the pure water supplied via factorypiping and is dissolved, and liquid Lq that has a desired specificresistance value (pure water, or to be more precise, carbonated water)is generated. More specifically, in the embodiment, carbon dioxide thatreduces specific resistance is incorporated into and is dissolved in thepure water, and is supplied on measurement table MTB or on wafer tableWTB as liquid Lq via liquid supply nozzle 131A. For incorporation(dissolution) of carbon dioxide (carbonic acid gas) into the pure water,various methods can be employed such as directly incorporating carbonicacid gas into the pure water, incorporating carbonic acid gas into thepure water via a hollow fiber film or the like. Or, air that containscarbonic acid gas can be dissolved into the pure water.

Then, according to instructions from controller 80, liquid temperatureadjustment unit 72 adjusts the temperature of liquid Lq so that thetemperature of the liquid is about the same level as the temperaturewithin the chamber (not shown) where the main body of the exposureapparatus is housed. In this case, controller 80 controls the flowamount of liquid Lq supplied via liquid supply nozzle 131A by adjustingthe degree of opening of flow control electromagnetic valves 86A and 86Bin a state where the flow amount ratio of pure water and carbon dioxideis maintained. However, as a matter of course, the temperature of theliquid and the flow amount can also be adjusted by arranging a flowcontrol valve inside or in the vicinity of liquid temperature adjustmentunit 72.

Liquid recovery unit 139 includes a tank of the liquid, a suction pump,and a valve for controlling the recovery/stop of the liquid via arecovery pipe and the like. As the valve, it is desirable to use a flowcontrol valve corresponding to the valve on liquid supply unit 138 sidedescribed earlier.

Refractive index n of the pure water to the ArF excimer laser beam isapproximately 1.44. In the pure water, the wavelength of illuminationlight IL is 193 nm×1/n, shorted to around 134 nm. In the case of theembodiment, as liquid Lq, the water solution previously described inwhich carbon dioxide is dissolved is used. Therefore, in a strict sense,the refractive index differs with pure water according to the ratio ofcarbon dioxide that has been incorporated. However, since theincorporation ratio of carbon dioxide is small, refractive index n ofliquid Lq to the ArF excimer laser beam will not be much different fromthe value above.

Liquid immersion unit 132 that includes liquid supply nozzle 131A andliquid recovery nozzle 131B operates under the control of maincontroller 50 (refer to FIG. 6). Main controller 50 supplies liquid Lqto the space in between tip lens 191 and wafer W via liquid supplynozzle 131A and also recovers liquid Lq from the space in between tiplens 191 and wafer W via liquid recovery nozzle 131B. In this case, maincontroller 50 performs control so that the amount of liquid Lq suppliedto the space in between tip lens 191 and wafer W from liquid supplynozzle 131A is constantly equal to the amount of liquid Lq recoveredfrom the space in between tip lens 191 and wafer W via liquid supplynozzle 131A. Accordingly, a constant amount of liquid Lq (refer toFIG. 1) is held or retained in the space between tip lens 191 and waferW. In this case, liquid Lq held in the space between tip lens 191 andwafer W is constantly replaced.

In the case when measurement stage MST is also positioned belowprojection unit PU, liquid Lq can be filled in the space betweenmeasurement table MTB and tip lens 191.

In the description above, for the sake of simplicity of the description,the case has been described where the number of nozzles arranged for theliquid supply nozzle and the liquid recovery nozzle is one each.However, the arrangement is not limited to this, and as is disclosed in,for example, the pamphlet of International Publication WO99/49504, anarrangement that has many nozzles can be employed. Further, anarrangement disclosed in, for example, European Patent ApplicationPublication No. 1,598,855 or in the pamphlet of InternationalPublication WO2004/090634 and the like can also be employed in liquidimmersion unit 132. The point is, as long as the liquid can be suppliedto the space between the optical member (tip lens) at the lowest endconfiguring projection optical system PL and wafer W, the arrangement ofliquid immersion unit 132 can be of any arrangement whatsoever.

As is shown in FIG. 1, on the +Y side of projection unit PU, an off-axisalignment system (hereinafter shortened to “alignment system”) ALG thatoptically detects marks subject to detection such as alignment marks orthe like on wafer W is arranged. As alignment system ALG, sensors ofvarious methods can be used. However, in the embodiment, a sensor by theimage-processing method is used. Details on sensors by theimage-processing method are disclosed in, for example, Kokai (JapanesePatent Unexamined Application Publication) No. 4-65603, thecorresponding U.S. Pat. No. 5,493,403 and the like. The imaging signalsfrom alignment system ALG are sent to main controller 50 (refer to FIG.6). As long as the national laws in designated states or elected states,to which this international application is applied, permit, the abovedisclosures of the publication and the U.S. patent are incorporatedherein by reference.

As is shown in FIGS. 1 and 2, stage unit 150 is provided with a baseplate 112, a wafer stage WST and measurement stage MST arranged abovethe upper surface of base plate 112, an interferometer system 118 (referto FIG. 6) for measuring the position of stages WST and MST, and a stagedrive system 124 (refer to FIG. 6) for driving stages WST and MST usinglinear motors or the like.

On the bottom surfaces of wafer stage WST and measurement stage MST,non-contact bearings (not shown) such as for example, static airbearings (that is, air bearings (also called air pads)) are arranged ina plurality of areas, and by means of the static pressure of thepressurized air blowing out from the static air bearings toward theupper surface of base plate 112, wafer stage WST and measurement stageMST are supported by levitation above the upper surface of base plate112 via a clearance of around several μm. Further, stages WST and MSTare each driven (including the θz rotation) independently within the XYplane by stage drive system 124. The position of wafer stage WST andmeasurement stage MST within the stage movement plane (the XY plane) andthe rotation position around each coordinate axis are detected byinterferometer system 118. In FIG. 1, in order to simplify thedescription, only a Y-axis interferometer 116 for measuring the positionof wafer stage WST in the Y-axis direction and a Y-axis interferometer117 for measuring the position of measurement stage MST in the Y-axisdirection are shown. The measurement values of interferometer system 118(116, 117) are sent to main controller 50, and main controller 50controls the position (and velocity) of wafer stage WST and measurementstage MST via stage drive system 124 based on the measurement values ofinterferometer system 118.

More specifically, as is shown in FIG. 1, wafer stage WST is providedwith a wafer stage main body 91 that has the air bearings describedabove arranged on its bottom surface, and a wafer table WTB mounted onwafer stage main body 91 via a Z-leveling mechanism (not shown)(including an actuator such as, for example, a voice coil motor) thatmoves finely with respect to wafer stage main body 91 in the Z-axisdirection, the rotation direction around the X-axis (the θx direction),and the rotation direction around the Y-axis (the θy direction).

On wafer table WTB, a wafer holder (not shown) is arranged that holdswafer W by vacuum suction or the like. The wafer holder is provided witha plate-shaped main body section, and a plate 93 (refer to FIGS. 1 and2) that has a circular opening formed in the center whose diameter isaround 0.1 to 2 mm larger than that of wafer W, fixed to the uppersurface of the main body section. On the area of the main body sectionwithin the circular opening of plate 93, many pins are arranged andwafer W is vacuum suctioned in a state where wafer W is supported by thepins. In this case, in the state where wafer W is vacuum suctioned, thesurface of wafer W and the surface of plate 93 are substantially flushwith each other. On the entire surface of plate 93, a liquid repellentmaterial (water repellent material) such as a fluorinated resinmaterial, an acrylic resin material or the like is coated and a liquidrepellent film is formed. Further, on the surface of wafer W, a resist(a sensitive material) is coated, and by the coated resist a resist filmis formed. In this case, as the resist film, it is desirable to use afilm that is liquid repellent to liquid Lq used for liquid immersion.Further, on the surface of wafer W, a top coat film (layer) can also beformed covering the resist film. As the top coat film, it is desirableto use a film that is liquid repellent to liquid Lq used for liquidimmersion. The top coat film has at least one of the followingfunctions: a protective function of protecting the resist film fromliquid Lq, an elution prevention function of preventing materials thatconstitute the resist film from eluting into liquid Lq, and a reflectionprevention function of preventing the reflection of illumination lightIL.

As is shown in FIG. 1, measurement stage MST is provided with ameasurement stage main body 92 that has the air bearings described abovearranged on its bottom surface, and a measurement table MTB mounted onmeasurement stage main body 92 via Z-leveling mechanism (not shown).

Measurement table MTB includes a hollow rectangular-parallelepipedhousing 120 (refer to FIG. 5) that has an opening on the upper surfaceand a plate member 101 of a predetermined thickness formed by a liquidrepellent material such as polytetrafluoroethylene (Teflon (brand name))that closes or covers the upper surface of housing 120, and has arectangular-parallelepiped appearance whose size in the height directionis much more smaller than the size in the width direction and the sizein the depth direction.

In plate member 101, as is shown in FIG. 4, which is a planar view ofmeasurement table MTB, a rectangular opening 101 a whose longitudinaldirection is in the Y-axis direction, a rectangular opening 101 b whosesize in the X-axis direction serving as the longitudinal direction issubstantially the same as opening 101 a, and three circular openings 101d, 101 e, and 101 f are formed.

On the inner side of opening 101 b of plate member 101 and underneathopening 101 b inside housing 120, an illuminance monitor (irradiationamount monitor) 122 is placed, as is shown in FIG. 5. Illuminancemonitor 122, as is shown in FIG. 5, is provided with a glass member 126made of glass, from materials such as synthetic silica glass or calciumfluorite, an optical sensor 128, which is fixed on the lower surface ofglass member 126 without hardly any gap and the like. Optical sensor 128has a photodetection surface of a predetermined area that can receivealmost all of illumination light IL irradiated on exposure area IA(refer to FIG. 4) described earlier shown in FIG. 5, and includes agroup of photoelectric elements such as a plurality of siliconphotodiodes (or photo multiplier tubes) that are sensitive to light inthe same wavelength region as illumination light IL (e.g. wavelength ofaround 300 nm to 100 nm) and also have a high response frequency fordetecting illumination light IL.

As is shown in FIG. 5, glass member 126 has a shape that faces the innersurface side and the lower surface side of opening 101 b of plate member101 via a predetermined gap. In this case, the size of the width of agap B between opening 101 b and the upper side surface of glass member126 is set, for example, at around 0.3 mm.

Glass member 126 engages from above with a support member 130 arrangedon the upper surface of the bottom wall of housing 120. Morespecifically, support member 130 has a frame shape with a predeterminedwidth that encloses optical sensor 128 in a planar view (when viewedfrom above), and on the lower surface in the outer periphery section ofglass member 126, a step section that engages with the upper end sectionof support member 130 is formed. On glass member 126, a lightattenuating film 129 made of a metal film such as chromium that reducesor attenuates illumination light IL is formed on the entire uppersurface, and further on the light attenuating film, a liquid repellentmaterial (water repellent material) such as a fluorinated resinmaterial, an acrylic resin material or the like is coated and a liquidrepellent film WRF is formed. In the embodiment, the upper surface ofliquid repellent film WRF and the upper surface of plate member 101 areset substantially on the same surface (flush with each other).

Meanwhile, on the lower surface of glass member 126, a light shieldingfilm 127 is formed, made of a metal film such as chromium that coversthe area excluding a rectangular area in the center. Light shieldingfilm 127 cuts the stray light (refer to the thick solid line arrows inFIG. 5) that enters glass member 126 via gap B as is shown in FIG. 5.

Illuminance monitor 122 of the embodiment has a configuration similar tothe illuminance monitor (illumination amount monitor) whose details aredisclosed in, for example, Kokai (Japanese Patent Unexamined ApplicationPublication) No. 6-291016, the corresponding U.S. Pat. No. 5,721,608 andthe like, and measures the illuminance of illumination light IL vialiquid Lq on the image plane of projection optical system PL. Detectionsignals (photoelectric conversion signals) of optical sensor 128 thatconstitutes a part of illuminance monitor 122 are supplied to maincontroller 50 via a hold circuit (not shown) (e.g. a peak hold circuit)and an analog/digital (A/D) converter (not shown). As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the above disclosures ofthe publication and the U.S. patent are incorporated herein byreference.

The side surface of glass member 126 at least in the area that facesplate member 101 and the inner wall surface of opening 101 b in platemember 101 that faces glass member 126 are liquid repellent, due to aliquid repellent treatment applied. The liquid repellent treatment canbe performed by coating the liquid repellent material such as thefluorinated resin material, the acrylic resin material or the like,previously described.

Further, on the bottom wall of housing 120 in the vicinity of supportmember 130, an discharging hole 120 a is formed. Discharging hole 120 aconnects to a recovery section (not shown) via a piping (not shown). Therecovery section is provided with a vacuum system, a vapor-liquidseparator that includes a tank that can hold liquid Lq and the like. Therecovery section recovers liquid Lq that has entered within housing 120via gap B regardless of the liquid repellent treatment.

Inside opening 101 a of plate member 101, fiducial mark plate FM thathas a rectangular shape in a planar view is placed as is shown in FIG.4. In this case, between fiducial mark plate FM and plate member 101, agap A of around 0.3 mm for example is formed surrounding fiducial markplate FM. The upper surface of fiducial mark plate FM is set atsubstantially the same height as (flush with) the surface of platemember 101. On the surface of fiducial mark plate FM, three pairs offirst fiducial marks RM₁₁ to RM₃₂ that can be simultaneously measuredpair by pair by the pair of reticle alignment detection systems RAa andRAb previously described and three second fiducial marks WM₁ to WM₃detected by alignment system ALG are formed in a predeterminedpositional relationship. Each of these fiducial marks are formed ofaperture patterns made by patterning on a chromic layer formed coveringalmost all of the surface of a member configuring fiducial mark plate FM(e.g. ultra low-thermal expansion glass-ceramic, for example, such asClearCeram (brand name)) at the predetermined positional relationshipreferred to above. Each fiducial mark can also be formed of patterns(residual patterns) of aluminum or the like.

In the embodiment, as is disclosed in, for example, Kokai (JapanesePatent Unexamined Application Publication) No. 5-21314, thecorresponding U.S. Pat. No. 5,243,195 and the like, the first fiducialmark RM_(j1), RM_(j2) (j=1 to 3) described above can be measuredsimultaneously by the pair of reticle alignment detection systems RAaand RAb via liquid Lq, and the arrangement of each of the fiducial marksabove is also determined so that the second fiducial mark WM_(j) can bemeasured simultaneously with the measurement of the first fiducial markRM_(j1), RM_(j2) without going through liquid Lq. As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the above disclosures ofthe publication and the U.S. patent are incorporated herein byreference. Further, the upper surface of fiducial mark plate FM issubstantially flat, and can be used as a reference surface of a multiplepoint focal position detection system. On the upper surface of fiducialmark plate FM, although it is not shown, a liquid repellent film made ofthe liquid repellent material such as the fluorinated resin material,the acrylic resin material or the like, previously described is formedon the upper section of the chromic layer described above.

To the side surface of fiducial mark plate FM in at least the area thatfaces plate member 101 and the inner wall surface of opening 101 a inplate member 101 that faces fiducial mark plate FM, liquid repellenttreatment is applied in a similar manner as is previously described.Further, on the bottom wall of housing 120 also in the vicinity offiducial mark plate FM, a discharging hole similar to discharging hole120 a is formed, and this discharging hole connects to the vacuum systemof the recovery section previously described.

On the inner side of opening 101 d of plate member 101 and below opening101 b inside housing 120, an uneven illuminance measuring instrument 104that has a pattern plate 103 of a circular shape when viewed from aboveis placed. Between pattern plate 103 and plate member 101, a gap D thathas a width size of around 0.3 mm, for example, is formed surroundingpattern plate 103.

Uneven illuminance measuring instrument 104 has pattern plate 103referred to above and a sensor (not shown) consisting of a photoelectricelement (such as a silicon photodiode or a photo multiplier tubereferred to earlier) placed below the pattern plate. Pattern plate 103is made of glass from materials such as synthetic silica glass as inglass member 126 described earlier, and on its surface a light shieldingfilm such as chromium is formed that has a pinhole 103 a serving as alight transmitting section formed in the center. And, on the shieldingfilm, the liquid repellent film made of the liquid repellent materialsuch as the fluorinated resin material, the acrylic resin material orthe like previously described is formed.

Uneven illuminance measuring instrument 104 referred to above has aconfiguration similar to the uneven illuminance measuring instrumentwhose details are disclosed in, for example, Kokai (Japanese UnexaminedPatent Application Publication) No. 57-117238 and the corresponding U.S.Pat. No. 4,465,368 and the like, and measures the uneven illumination ofillumination light IL via liquid Lq on the image plane of projectionoptical system PL. Then, detection signals (photoelectric conversionsignals) of the sensor configuring the uneven illuminance measuringinstrument are supplied to main controller 50 via a hold circuit (notshown) (e.g. a peak hold circuit) and an analog/digital (A/D) converter(not shown). As long as the national laws in designated states orelected states, to which this international application is applied,permit, the above disclosures of the publication and the U.S. patent areincorporated herein by reference.

Inside opening 101 e of plate member 101, a slit plate 105 that has acircular shape in a planar view is placed in a state where the surfaceof slit plate 105 is substantially on the same surface as (flushwith)the surface of plate member 101. Between slit plate 105 and platemember 101, a gap E that has a width size of around 0.3 mm, for example,is formed surrounding slit plate 105. Similar to pattern plate 103, slitplate 105 is made of synthetic silica glass and has a light shieldingfilm made of chromium or the like formed on the surface of the syntheticsilica glass, and has slit patterns serving as a light transmittingsection, extending in the X-axis direction and Y-axis direction atpredetermined places on the light shielding film. And, on the lightshielding film, the liquid repellent film made of the liquid repellentmaterial such as the fluorinated resin material, the acrylic resinmaterial or the like previously described is formed. Slit plate 105configures a part of an aerial image measuring instrument that measuresthe light intensity of an aerial image of a pattern projected byprojection optical system PL. In the embodiment, inside measurementtable MTB (housing 120) underneath slit plate 105, a photodetectionsystem is arranged that receives illumination light IL via the slitpattern, irradiated on plate member 101 via projection optical system PLand liquid Lq, which constitutes an aerial image measuring instrumentsimilar to the one disclosed in, for example, Kokai (Japanese UnexaminedPatent Application Publication) No. 2002-14005 and the correspondingU.S. Patent Application Publication No. 2002/0041377. As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the above disclosures ofthe Kokai publication and the U.S. Patent application publication areincorporated herein by reference.

Inside opening 101 f of plate member 101, a wavefront aberrationmeasurement pattern plate 107 that has a circular shape in a planar viewis placed in a state where the surface of wavefront aberrationmeasurement pattern plate 107 is substantially on the same surface as(flush with) the surface of plate member 101. Similar to pattern plate103, wavefront aberration measurement pattern plate 107 is made ofsynthetic silica glass and has a light shielding film made of chromiumor the like formed on the surface of the synthetic silica glass, and hasa circular opening formed in the center of the light shielding film.And, on the light shielding film, the liquid repellent film made of theliquid repellent material such as the fluorinated resin material, theacrylic resin material or the like previously described is formed.Inside measurement table MTB (housing 120) underneath wavefrontaberration measurement pattern plate 107, for example, a photodetectionsystem that includes a microlens array that receives illumination lightIL via projection optical system PL and liquid Lq is arranged, whichconstitutes a wavefront aberration measuring instrument. The details ofthe instrument are disclosed in, for example, the pamphlet ofInternational Publication WO99/60361, and the corresponding EuropeanPatent Publication No. 1,079,223 Description. As long as the nationallaws in designated states or elected states, to which this internationalapplication is applied, permit, the above disclosures of the pamphlet ofInternational Publication and the European Patent Publication areincorporated herein by reference.

The liquid repellent treatment similar to the one previously describedis applied to each of the following areas: the areas on the sidesurfaces of pattern plate 103, slit plate 105, and wavefront aberrationmeasurement pattern plate 107 that face at least plate member 101, theinner wall surface of opening 101 d of plate member 101 that facespattern plate 103, the inner wall surface of opening 101 e of platemember 101 that faces slit plate 105, and the inner wall surface ofopening 101 f of plate member 101 that faces wavefront aberrationmeasurement pattern plate 107. Further, on the bottom wall of housing120, an discharging hole similar to discharging hole 120 a describedearlier is formed each in the vicinity of pattern plate 103, in thevicinity of slit plate 105, and in the vicinity of wavefront aberrationmeasurement pattern plate 107, and these discharging holes connect tothe vacuum system of the recovery section previously described.

Although it is omitted in the drawings, in the embodiment, insidehousing 120, because photodetection elements (sensors) are arranged thatconfigure the various measuring instruments described earlier, in orderto prevent the influence of heat generation of the photodetectionelements as much as possible, a cooling mechanism for cooling thephotodetection elements and housing 120 is arranged. As the coolingmechanism of the photodetection elements, a combination of a heat sinkarranged on the bottom wall of housing 120 and a Peltier elementconnected to the heat sink can be given. Further, as the coolingmechanism for housing 120, for example, a mechanism by the liquidcooling method that circulates a cooling liquid inside the piping can beemployed.

From the viewpoint of suppressing the influence of heat, for example, inthe aerial image measuring instrument or in the wavefront aberrationmeasuring instrument, the part of the instrument installed inmeasurement stage MST can be limited to the optical system or the like.

Further, in exposure apparatus 100 of the embodiment, although it is notshown in FIG. 1, a multiple point focal position detection system by anoblique incident method similar to the one disclosed in, for example,Kokai (Japanese Patent Unexamined Application Publication) No. 6-283403(the corresponding U.S. Pat. No. 5,448,332) or the like that includes anirradiation system 110 a and a photodetection system 110 b (refer toFIG. 6) is arranged.

FIG. 6 shows a main configuration of a control system of exposureapparatus 100. The control system is mainly composed of main controller50, which is constituted by a microcomputer (or a workstation) and hascontrols the overall operation of the entire apparatus. In FIG. 6,reference numeral 143 indicates a group of measuring instruments such asilluminance monitor 122, uneven illuminance measuring instrument 104,the aerial image measuring instrument, the wavefront aberrationmeasuring instrument and the like arranged on measurement table MTB.

Next, a parallel processing operation using both wafer stage WST andmeasurement stage MST in exposure apparatus 100 of the embodiment willbe described, referring to FIG. 2 or the like. During the followingoperation, main controller 50 controls liquid immersion unit 132 andconstantly fills in the space below tip lens 191 of projection opticalsystem PL with liquid Lq.

FIG. 2 shows a state where exposure of wafer W (in this case, as anexample, the wafer is to be the last wafer of a specific lot (one lothas 25 to 50 wafers)) on wafer stage WST is performed by a step-and-scanmethod. At this point, measurement stage MST is waiting at apredetermined waiting position where it does not bump into or collidewith wafer stage WST.

The above-mentioned exposure operation is performed by repeating amovement operation in between shots where wafer stage WST is moved to ascanning starting position (acceleration starting position) for exposureof each of the shot areas on wafer W and a scanning exposure operationwhere the pattern formed on reticle R is transferred onto each shot areaby the scanning exposure method, based on results of wafer alignmentsuch as, for example, Enhanced Global Alignment (EGA) that has beenperformed in advance. The exposure operation above is performed in astate where liquid Lq is held in the space between tip lens 191 andwafer W.

Then, on the wafer stage WST side, at the point where exposure of waferW has been completed, main controller 50 moves measurement stage MST(measurement table MTB) until it comes to a position close to the −Yside of wafer stage WST located at an exposure end position, bycontrolling stage drive system 124 based on the measurement values ofinterferometer system 118. At this point, main controller 50 monitorsthe measurement values of interferometer system 118, of theinterferometer that measures the position of each table in the Y-axisdirection so that a non-contact state is maintained between measurementtable MTB and wafer table WTB, distanced apart in the Y-axis directionby, for example, around 300 μm. The arrangement, however, is not limitedto this, and main controller 50 can make the −Y side surface ofmeasurement table MTB come into contact with the +Y side surface ofwafer table WTB.

Next, main controller 50 begins the operation of simultaneously drivingwafer stage WST and measurement stage MST in the +Y direction whilemaintaining the positional relation of wafer table WTB and measurementtable MTB in the Y-axis direction.

When wafer stage WST and measurement stage MST are simultaneously movedby main controller 50 in the manner described above, liquid Lq that hasbeen held in the space between tip lens 191 of projection unit PU andwafer W sequentially moves over the following areas along with themovement of wafer stage WST and measurement stage MST to the +Y side;wafer W→plate 93→measurement table MTB. That is, liquid Lq is in a statewhere it is held in the space between measurement table MTB and tip lens191.

Next, main controller 50 controls the position of wafer stage WST bycontrolling stage drive system 124 based on the measurement values ofinterferometer system 118 so that wafer stage WST is moved to apredetermined wafer exchange position and also exchanges the wafer tothe first wafer of the following lot, and in parallel with theoperation, main controller 50 also performs a predetermined measurementusing measurement stage MST when necessary.

As an example of the predetermined measurement, for example, baselinemeasurement of alignment system ALG can be given.

More specifically, main controller 50 detects the first fiducial mark inpairs on fiducial mark plate FM arranged on measurement stage MST andthe corresponding reticle alignment marks on reticle R at the same timeusing reticle alignment systems RAa and RAb previously described, anddetects the positional relation between the first fiducial mark in pairsand the corresponding reticle alignment marks. At this point, the firstfiducial mark is detected via projection optical system PL and liquidLq. Further, at the same time, by also detecting second fiducial markson fiducial mark plate FM with the alignment system ALG, main controller50 detects the positional relation between the detection center ofalignment system ALG and the second fiducial mark.

Then, based on the positional relation between the first fiducial markin pairs and the corresponding reticle alignment marks and thepositional relation between the detection center of alignment system ALGand the second fiducial marks obtained above, and the known positionalrelation between the first fiducial mark in pairs and the secondfiducial marks, main controller 50 obtains the distance (or thepositional relation) between the projection center of the reticlepattern by projection optical system PL and the detection center ofalignment system ALG, that is, obtains the baseline of alignment systemALG.

Then, at the stage where the operations on both stages WST and MST havebeen completed, main controller 50 sets measurement stage MST and waferstage WST to the neighboring state that has been described earlier andsimultaneously moves both stage WST and MST in the −Y direction,reversing the operation above while maintaining the positional relationof wafer stage WST and measurement stage MST in the Y-axis direction andholding liquid Lq under projection optical system PL so as to move waferstage WST (the wafer) to the position under projection optical systemPL, and then makes measurement stage MST withdraw to a predeterminedposition.

Then, main controller 50 executes wafer alignment and the exposureoperation by the step-and-scan method of a new wafer, and sequentiallytransfers the reticle pattern onto the plurality of shot areas on thewafer. Hereinafter, main controller 50 repetitively performs the sameoperation.

In the description above, the case has been described where baselinemeasurement is performed as the measurement operation, however, thepresent invention is not limited to this, and at least one ofilluminance measurement, uneven illuminance measurement, aerial imagemeasurement, wavefront aberration measurement can be performed using themeasuring instrument group of measurement stage MST while wafer exchangeof each wafer is performed on the wafer stage WST side, and themeasurement results can be reflected in the exposure of the wafers thatwill be performed later on. To be more specific, for example, imageforming characteristics correction controller 52 can perform adjustmentof projection optical system PL based on the measurement results.Further, the apparatus does not necessarily have to be provided with allof the group of measuring instruments such as the illuminance monitor,the uneven illuminance measuring instrument, the aerial image measuringinstrument, the wavefront aberration measuring instrument and the likearranged on measurement table MTB, and only a part of the instrumentsmay be installed in measurement stage MST as necessary.

Further, while the series of operations above are being performed, maincontroller 50 continues to fill in the space of the optical path on theimage plane side of projection optical system PL by controlling liquidimmersion unit 132 and supplying a predetermined amount of liquid Lqfrom liquid supply nozzle 131A as well as recovering a predeterminedamount of liquid Lq from liquid recovery nozzle 131B.

Further, main controller 50 controls controller 80 and supplies liquidLq whose specific resistance is reduced from liquid supply nozzle 131Aof liquid immersion unit 132. Main controller 50 decides the supplyamount of liquid Lq that is to be supplied from liquid supply nozzle131A in order to continue filling the space of the optical path on theimage plane side of projection optical system PL based on the filmproperty (such as the contact angle with liquid Lq) of the surface ofwafer W and various conditions such as the scanning velocity of wafer Wduring exposure, and inputs command values of the supply amount that hasbeen decided into controller 80. Controller 80 controls flow controlelectromagnetic valve 86A so that the amount of liquid Lq correspondingto the command values of the supply amount from main controller 50 issupplied from liquid supply nozzle 131A, and also controls flow controlelectromagnetic valve 86B while monitoring specific resistance indicator76 so that the specific resistance value of liquid Lq supplied fromliquid supply nozzle 131A reaches a predetermined specific resistancevalue. In the embodiment, the specific resistance value of liquid Lq isadjusted to 10[MΩ·cm] or under, preferably from 0.1 to 1.0·[MΩ·cm].

In the embodiment, because carbon dioxide (CO₂) is incorporated into andis dissolved in the pure water, depending on the amount of the carbondioxide dissolved, the refractive index to illumination light IL maydiffer with the pure water that does not incorporate carbon dioxide, andthere may be a case where the difference in the refractive index cannotbe ignored. In such a case, the incorporation ratio of carbon dioxide tothe pure water is a known desired value, and the refractive index of theliquid after the incorporation can be measured in advance. For example,the relation between the incorporation ratio of carbon dioxide to thepure water and the refractive index of the liquid after theincorporation can be stored in main controller 50, and based on thestored information, main controller 50 can control at least a part ofprojection optical system PL via image forming characteristicscorrection controller 52 taking into consideration the refractive indexof the liquid (pure water) due to the dissolution of carbon dioxide (apredetermined substance). In such a case, the pattern of reticle R canbe transferred onto wafer W via projection optical system PL and liquidLq with good precision without being affected by the change in therefractive index of the liquid.

Further, in the case of incorporating and dissolving carbon dioxide inthe pure water, depending on the amount of the carbon dioxide dissolved,the transmittance to illumination light IL (or a light having the samewavelength as the exposure light) may differ with the pure water thatdoes not incorporate carbon dioxide, and there may be a case where thedifference in the transmittance cannot be ignored. In this case, byperforming a predetermined calculation based on results whenillumination light IL is received by illuminance monitor 122 in a statewhere carbon dioxide is not incorporated and when illumination light ILis received by illuminance monitor 122 in a state after the carbondioxide is incorporated, the transmittance change of the pure water(liquid) to illumination light IL (or the light having the samewavelength as the exposure light) due to the dissolution of carbondioxide (a predetermined substance) can be obtained. Accordingly, maincontroller 50 can perform dose control (control of the integratedexposure amount) to wafer W on scanning exposure, taking intoconsideration the transmittance change. For example, main controller 50performs dose control by switching the rough energy adjuster provided inillumination system ILS, by adjusting the pulsed energy or oscillationfrequency (repetition frequency) of illumination light IL emitted fromthe light source, or by controlling the scanning velocity of reticlestage RST and wafer stage WST or the like. In such a case, the patternof reticle R can be transferred onto wafer W via projection opticalsystem PL and liquid Lq with good precision without being affected bythe change in the transmittance of the liquid to illumination light IL(or the light having the same wavelength as the exposure light).

As is described above, according to exposure apparatus 100 of theembodiment, liquid immersion unit 132 has a mechanism of incorporating(dissolving) carbon dioxide that reduces specific resistance of liquidLq, which is supplied in order to form an liquid immersion area on afilm (a liquid repellent film, or a film formed by a resist (a resistfilm), or a top coat layer which is formed so as to cover the resist) ona member arranged on the light emitting side of tip lens 191, that is,on a part of measurement table MTB (a part of of at least one of platemember 101 and each of the measuring instruments), or a part of wafertable WTB (a part of at least one of plate 93 and wafer W). Therefore,charging of liquid Lq can be prevented or effectively suppressed, andgeneration of dielectric breakdown of the film on which the liquidimmersion area is formed can be effectively suppressed.

More specifically, for example, in the case of measuring illuminance,illuminance monitor 122 (optical sensor 128) receives illumination lightIL via liquid repellent film WRF and liquid Lq on liquid repellent filmWRF, and illuminance measurement of illumination light IL is performed.On such illuminance measurement, if an liquid immersion area of liquidLq that is charged is formed on liquid repellent film WRF, a discharge(dielectric breakdown) may occur between light attenuating film 129 (ametal membrane) and liquid Lq via liquid repellent film WRF and theremay be a possibility of damage occurring in liquid repellent film WRF.Further, by being in contact with liquid Lq that is charged, thevicinity of the contact surface to the liquid of liquid repellent filmWRF could be charged, and a discharge (dielectric breakdown) may occurbetween light attenuating film 129 (a metal membrane) provided underliquid repellent film WRF and liquid repellent film WRF, which may causedamage in liquid repellent film WRF. When liquid repellent film WRF isdamaged (deteriorated), the optical properties of liquid repellent filmWRF may become uneven or the liquid repellency may be reduced, and thuswater stains (water marks) may be generated.

However, in the embodiment, because carbon dioxide (carbonic acid gas)is dissolved in the pure water and liquid Lq whose specific resistanceis reduced is supplied from liquid supply nozzle 131A, charging ofliquid Lq can be prevented, which can effectively suppress the damage ofliquid repellent film WRF due to dielectric breakdown. Accordingly,illuminance measurement using illuminance monitor 122 can be executedwith high precision for over a long period of time, and by performingexposure of wafer W reflecting the measurement results, it becomespossible to perform exposure with high precision for over a long periodof time.

In the description above, the case has been described referring toilluminance monitor 122, however, by suppressing the charging of liquidLq, damage of the liquid repellent film on the upper surface ofmeasurement stage MST can be prevented. Further, by suppressing thecharging of liquid Lq, damage (deterioration) can be suppressed not onlyof the liquid repellent film on the upper surface of measurement stageMST, but also of the liquid repellent film on the upper surface of plate93 of wafer stage WST.

Further, according to exposure apparatus 100 of the embodiment, scanningexposure for transferring the circuit pattern of reticle R onto wafer Wis performed by illuminating reticle R by illumination light IL andsynchronously moving reticle R and wafer W with respect to illuminationlight IL, via projection optical system PL and liquid Lq. On thisscanning exposure, if an liquid immersion area of liquid Lq that ischarged is formed on the resist film (or the top coat film) on thesurface of wafer W, a discharge (dielectric breakdown) may occur betweenliquid Lq and the base material of wafer W (such as silicon) via theresist film (or via the top coat film and the resist film) and there maybe a possibility of damage or modification occurring in the resist film(or the top coat film and the resist film). Further, by being in contactwith liquid Lq that is charged, the vicinity of the contact surface tothe liquid of the resist film (or the top coat film) could be charged,and a discharge (dielectric breakdown) may occur between the resist film(or the top coat film) and the base material of wafer W (such assilicon), which may cause damage or modification in the resist film (orthe top coat film). When the resist film (or the top coat film) isdamaged, liquid Lq may seep or infiltrate in from the damaged sectionand a defect may occur in the pattern formed on wafer W. Further, whenthe resist film (or the top coat film) is damaged or modified, a changemay occur in reaction characteristics of illumination light IL toirradiation, which may prevent the desired pattern from being formed onwafer W.

However, in the embodiment, because carbon dioxide (carbonic acid gas)is dissolved in the pure water and liquid Lq whose specific resistancevalue is reduced is supplied from liquid supply nozzle 131A, thedielectric breakdown of the resist film (in the case a top coat layer isformed on the resist film, the resist film and top coat layer) on waferW is effectively suppressed.

Further, in exposure apparatus 100 of the embodiment, by performingexposure with high resolution and a larger depth of focus than in theair by means of the liquid immersion exposure, the pattern of reticle Rcan be transferred with good precision on the wafer, and for example,transfer of a fine pattern that has a device rule of around 45 to 100 nmcan be achieved using the ArF excimer laser beam.

In the embodiment above, liquid which is pure water that has carbondioxide dissolved (carbonated water) is used as liquid Lq used forliquid immersion, however, it is a matter of course that the presentinvention is not limited to this. For example, if there are no adverseeffects on the devices formed on wafer W, chlorine can be dissolved inthe pure water in order to prevent liquid Lq from being charged.

Further, also in the case of using liquid other than the pure water, inorder to prevent deterioration of the film on the object which occursdue to the charging of the liquid by adjusting the specific resistanceof the liquid, it is preferable to use a liquid in which a predeterminedsubstance that can adjust the specific resistance of the liquid isincorporated and dissolved.

In the embodiment above, the case has been described where incorporationof the predetermined substance (carbon dioxide) into the liquid (purewater) is performed on the upstream side of liquid temperatureadjustment unit 72, however, the present invention is not limited tothis, and the predetermined substance can also be incorporated into anddissolved between the liquid adjustment mechanism, which performs atleast one of temperature adjustment and liquid flow control of theliquid, and the liquid supply nozzle.

For example, in the case there is a concern of microorganisms in liquidLq multiplying, the incorporation of carbon dioxide (carbonic acid gas)is preferably performed at a position as close as possible to the imageplane of projection optical system PL, such as at, for example, aposition immediately before supply nozzle 131A or within supply nozzle131A, so that the carbonic acid does not become a nutrient source formicroorganisms.

Further, at least a part of a member that forms the supply flow passageof liquid Lq can be made of a material that releases carbon dioxide(carbonic acid gas) into liquid Lq without using CO₂ dissolving tank 82,or in combination with CO₂ dissolving tank 82.

Regardless of adjustment in the specific resistance value of liquid Lq,in the case of forming an liquid immersion area, by the friction betweenliquid Lq and wafer W (including at least one of the top coat layer andthe resist film), the friction between liquid Lq and an object (such asplate 93 (including the liquid repellent film), plate member 101(including the liquid repellent film), pattern plate 103 (including theliquid repellent film), slit plate 105 (including the liquid repellentfilm), pattern plate (including the liquid repellent film), or fiducialmark plate FM (including the liquid repellent film)), the frictionbetween liquid Lq and nozzle members (such as 131A and 131B) or thelike, a possibility occurs of at least one of liquid Lq, wafer W, theobjects described above, and the nozzle members being charged.Therefore, it is preferable to have at least one of wafer W, the objectsdescribed above, and the nozzle member connected to the ground(earthed). By this arrangement, the charge of liquid Lq can be removedeven when liquid Lq becomes charged. Further, adherence of foreignsubstances such as particles on the object, due to the charge of theobjects described above or the charge of the nozzle member, can beprevented, and thus contamination of liquid Lq and wafer W due to theforeign substances can be prevented. As a matter of course,deterioration of at least one of the top coat layer and the resist filmformed on wafer W, and the liquid repellent film on the objectsdescribed above can also be prevented.

Further, as is disclosed in the pamphlet of International PublicationWO2005/031824 and the like, the charge of liquid Lq supplied to thespace on the image plane side of projection optical system PL can beremoved. In this case, liquid Lq supplied to the space on the imageplane side of projection optical system PL can be kept from beingcharged more certainly.

Further, in the vicinity of the space on the image plane side ofprojection optical system PL, a neutralization apparatus (ionizer) asthe one disclosed in Kokai (Japanese Patent Unexamined ApplicationPublication) No. 2003-332218 or the like can be arranged, and at leastone of liquid Lq, wafer W, the objects, and the nozzle member can beneutralized by supplying ions (negative ions) to the space on the imageplane side of projection optical system PL (the periphery of liquid Lq).In this case, even if at least one of liquid Lq, wafer W, the objects,and the nozzle member is charged, the neutralization apparatus removesthe electricity. Therefore, it is possible to prevent liquid Lq, waferW, the object described above and the nozzle member, and the like fromattracting contaminants such as particles, and thus contamination ofliquid Lq and/or wafer W can also be prevented. Further, by blowing gasthat has a neutralization function (e.g. gas that contains ions) in thevicinity of a surface interface of an liquid immersion area formedlocally by liquid Lq, the gas can have not only the neutralizationfunction but also a leakage prevention function of the liquid that formsthe liquid immersion area. In the case exposure apparatus 100 has a gasseal mechanism installed for preventing leaking of the liquid formingthe liquid immersion area as is disclosed in, for example, Kokai(Japanese Unexamined Patent Application Publication) No. 2004-289126 andthe corresponding U.S. Patent Application Publication No. 2006/0023189,the gas used in the gas seal mechanism can contain the ions.

Further, regardless of adjustment in the specific resistance value ofliquid Lq, in the case an liquid immersion area is formed on wafer W,wafer W (including at least one of the resist film and the top coatfilm) may be charged due to the friction between liquid Lq and wafer W.Because wafer W in a charged state attracts foreign substances such asparticles, wafer W may be contaminated.

Therefore, the resist film (or the top coat film) of the surface ofwafer W can be formed of a conductive substance so as to prevent thecharging of wafer W (including at least one of the resist film and thetop coat film). Or, the wafer holder that holds wafer W can be made of aconductive material, or a contact member made of a conductive materialthat comes into contact with wafer W held on the wafer holder can bearranged, so as to prevent the charging of wafer W (including at leastone of the resist film and the top coat film).

Further, the liquid repellent film formed on plate member 93 or the likecan be conductive.

Further, in the case there is a possibility of wafer W (including atleast one of the resist film and the top coat film) being carried out ina charged state, at least one of a carriage member or transport memberthat carries wafer W before exposure or after exposure can be made of aconductive material so as to release (remove) the electrical charge ofwafer W. Or, in order to remove the electricity of at least one of waferW carried onto wafer stage WST and wafer W carried from wafer stage WST,a unit for soaking (e.g. cleaning) wafer W with a conductive liquid(pure water that has carbon dioxide dissolved) can be arranged on thecarrier path or transport path of wafer W. Or a neutralization apparatussuch as an ionizer can be arranged along the carrier path of wafer W. Inthe case a liquid removal unit that removes, for example, drops ofliquid Lq remaining (adhering) on wafer W after exposure is installed inexposure apparatus 100, it is preferable to perform not only liquidremoval but also charge removal within the liquid removal unit. Further,in the case a temperature adjustment unit for performing temperaturecontrol of wafer W before wafer W is carried onto wafer stage WST isarranged in exposure apparatus 100, charge removal can be performed inthe temperature adjustment unit.

Further, in order to neutralize wafer W, a unit for soaking (e.g.cleaning) wafer W with a conductive liquid (pure water that has carbondioxide dissolved) or a neutralization apparatus such as an ionizer canbe arranged within a substrate processing unit (including at least oneof a coating unit that carries out pre-exposure wafer W to exposureapparatus 100 and a development unit into which wafer W that has beenexposed by exposure apparatus 100 is carried) that is connected toexposure apparatus 100. Or, in the development unit to which wafer Wthat has been exposed in exposure apparatus 100 is carried, a conductiverinsing liquid can be used when performing development of post-exposurewafer W. In the case an interface section is arranged between exposureapparatus 100 and the substrate processing unit, the neutralizationprocess of removing the charge from wafer W can be performed in theinterface section.

Further, in the embodiment above, the case has been described where theexposure apparatus is provided with measurement stage MST separatelyfrom wafer stage WST. However, the measurement stage does notnecessarily have to be arranged, and the various measuring instrumentssuch as illuminance monitor 122 including glass member 126 can bearranged on an object stage (wafer stage WST) on which the object ismounted. Even in such a case, measurement with high precision can beexecuted for over a long period of time by the aid of illuminancemonitor 122 and the like, and by performing exposure of wafer W with themeasurement results being reflected, it becomes possible to perform theexposure with high precision for over a long period of time.

In the embodiment above, the case has been described where the presentinvention is applied to a scanning exposure apparatus of thestep-and-scan method, however, the scope of the invention is naturallynot limited to this. More specifically, the present invention can alsobe applied to a projection exposure apparatus by the step-and-repeatmethod, and furthermore to an exposure apparatus by the step-and-stitchmethod, an exposure apparatus by the proximity method and the like.

Further, the present invention can also be applied to a multi-stage typeexposure apparatus that has a plurality of wafer stages for holding thewafer, as is disclosed in Kokai (Japanese Unexamined Patent Publication)No. 10-163099, Kokai (Japanese Unexamined Patent Publication) No.10-214783 and the corresponding U.S. Pat. No. 6,341,007, and in Kohyo(Japanese Unexamined Patent Publication) No. 2000-505958 and thecorresponding U.S. Pat. No. 5,969,441 and the like. As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the disclosures of each ofthe publications and the corresponding U.S. patents cited above arefully incorporated herein by reference.

Further, the exposure apparatus to which the liquid immersion methoddescribed above is applied employs the configuration where wafer W isexposed while the optical path space on the light-emitting side of theend optical element of projection optical system PL is filled withliquid (pure water). However, as is disclosed in the pamphlet ofInternational Publication WO2004/019128 and the corresponding U.S.Patent Application Publication No. 2005/0248856 and the like, theoptical path space on the light-incident side of the end optical elementof projection optical system PL can also be filled with liquid (purewater). As long as the national laws in designated states or electedstates, to which this international application is applied, permit, theabove disclosures of the Kokai publication and the U.S. Patentapplication publication are incorporated herein by reference.

Further, in the embodiment above, the exposure apparatus in which liquidis locally filled in the space between projection optical system PL andwafer W is employed, however, the present invention can also be appliedto an liquid immersion exposure apparatus that performs exposure in astate where the entire surface of the wafer subject to exposure issoaked in the liquid as is disclosed in, Kokai (Japanese UnexaminedPatent Publication) No. 6-124873, Kokai (Japanese Unexamined PatentPublication) No. 10-303114, and in U.S. Pat. No. 5,825,043 and the like.

In the embodiment above, a transmittance type mask is used, which is atransmissive mask on which a predetermined light shielding pattern (or aphase pattern or a light-reducing pattern) is formed. Instead of thismask, however, as is disclosed in, for example, U.S. Pat. No. 6,778,257,an electron mask on which a light-transmitting pattern, a reflectionpattern, or an emission pattern is formed according to electronic dataof the pattern that is to be exposed can also be used.

Further, as is disclosed in the pamphlet of International PublicationWO2001/035168, by forming interference fringes on wafer W, the presentinvention can also be applied to an exposure apparatus (lithographysystem) that forms line-and-space patterns on wafer W.

The present invention is not limited to the exposure apparatus formanufacturing semiconductors, and it can also be widely applied to anexposure apparatus used for manufacturing liquid crystal displays thattransfers a liquid crystal display device pattern onto a glass plate, anexposure apparatus used for manufacturing organic ELs, thin filmmagnetic heads, imaging devices (such as CCDs), micromachines, DNAchips, and the like. Further, the present invention can also be appliedto an exposure apparatus that transfers a circuit pattern onto a glasssubstrate or a silicon wafer not only when producing microdevices suchas semiconductors, but also when producing a reticle or a mask used inexposure apparatus such as an optical exposure apparatus, an EUVexposure apparatus, an X-ray exposure apparatus, and an electron beamexposure apparatus.

The light source of the exposure apparatus in the embodiment above isnot limited to the ArF excimer laser, and it is also possible to use apulsed laser light source such as the KrF excimer laser (outputwavelength 248 nm), the F₂ laser (output wavelength 157 nm), the Ar₂laser (output wavelength 126 nm), the Kr₂ laser (output wavelength 146nm), or the like, or an ultra high-pressure mercury lamp that emitsbright lines such as the g-line (wavelength 436 nm) or the i-line(wavelength 365 nm). Further, a harmonic generation unit of a YAG lasercan also be used. Besides such units, a harmonic may also be used thatis obtained by amplifying a single-wavelength laser beam in the infraredor visible range emitted by a DFB semiconductor laser or fiber laser,with a fiber amplifier doped with, for example, erbium (or both erbiumand ytteribium), and by converting the wavelength into ultraviolet lightusing a nonlinear optical crystal. Further, the projection opticalsystem is not limited to a reduction system, and the system may also bea system of equal magnification or a magnifying system.

Semiconductor devices are manufactured through the following steps: astep where the function/performance design of a device is performed; astep where a reticle based on the design step is manufactured; a stepwhere a wafer is manufactured using silicon materials; a lithographystep where the pattern formed on the reticle is transferred onto anobject such as a wafer by the liquid immersion exposure previouslydescribed using the exposure apparatus in the embodiment above; a deviceassembly step (including processes such as dicing process, bondingprocess, and packaging process); inspection step, and the like. In thiscase, in the lithography step, because the device pattern is formed onthe object executing the liquid immersion exposure method previouslydescribed using the exposure apparatus in the embodiment above, highintegration devices can be manufactured wit good yield.

While the above-described embodiment of the present invention is thepresently preferred embodiment thereof, those skilled in the art oflithography systems will readily recognize that numerous additions,modifications, and substitutions may be made to the above-describedembodiment without departing from the spirit and scope thereof. It isintended that all such modifications, additions, and substitutions fallwithin the scope of the present invention, which is best defined by theclaims appended below.

What is claimed is:
 1. An exposure apparatus that exposes an object viaa projection optical system and a liquid, the apparatus comprising: astage on which the object can be mounted and which moves in a lightemitting side of the projection optical system; a liquid immersionmember having a supply port from which the liquid is supplied to thelight emitting side of the projection optical system; and a first memberwhich has a transmissive member and which is placed on the stage, thestage being movable to a position at which the first member comes intocontact with the liquid and at which the first member is irradiated witha measurement light from the projection optical system through theliquid, wherein the measurement light enters the transmissive member viaa first surface of the transmissive member and exits from thetransmissive member via a second surface of the transmissive member, andthe first member has a light-limiting material arranged on a portion ofthe second surface of the transmissive member.
 2. The exposure apparatusaccording to claim 1, wherein the transmissive member is a glass member,and the light-limiting material includes a light attenuating material.3. The exposure apparatus according to claim 2, wherein the lightlimiting material includes a metal material.
 4. The exposure apparatusaccording to claim 1, wherein the first member has a liquid repellentfilm formed on the first surface of the transmissive member, and theliquid comes into contact with a surface of the liquid repellent film ofthe first member.
 5. The exposure apparatus according to claim 1,wherein a surface of the first member with which the liquid comes intocontact is liquid repellent to the liquid.
 6. The exposure apparatusaccording to claim 5, wherein the first member has a film of afluorinated resin material or an acrylic resin material, and the surfaceof the first member includes a surface of the film.
 7. The exposureapparatus according to claim 1, further comprising: a measurement deviceincluding the first member and a photodetection system that receives themeasurement light having passed through the second surface of thetransmissive member.
 8. The exposure apparatus according to claim 1,further comprising: a second member which is placed on the stage suchthat the second member surrounds the first member.
 9. The exposureapparatus according to claim 8, wherein the stage comprises a recoverydevice having a discharge opening via which the liquid supplied from thesupply port is discharged, and the recovery device recovers the liquidflowing in through a gap formed between the second member and the firstmember.
 10. The exposure apparatus according to claim 1, wherein apredetermined substance that adjusts specific resistance of the liquidis dissolved in the liquid, and the exposure apparatus further comprisesa controller that determines an exposure condition based on atransmittance change of the liquid after mixture of the predeterminedsubstance in the liquid.
 11. A device manufacturing method comprising:exposing a substrate using the apparatus defined in claim 1; andprocessing the exposed substrate.
 12. An exposure method of exposing anobject on a stage via a projection optical system and a liquid, themethod comprising: supplying the liquid in a space between theprojection optical system and the stage; and moving the stage on which afirst member is placed, the stage being movable to a position at whichthe first member comes into contact with the liquid and at which thefirst member is irradiated with a measurement light from the projectionoptical system through the liquid, wherein the first member has atransmissive member, the measurement light enters the transmissivemember via a first surface of the transmissive member and exits from thetransmissive member via a second surface of the transmissive member, andthe first member has a light-limiting material arranged on a portion ofthe second surface of the transmissive member.
 13. The exposure methodaccording to claim 12, wherein the light limiting material includes alight attenuating material.
 14. The exposure method according to claim12, wherein the light limiting material includes a metal material. 15.The exposure method according to claim 13, further comprising: receivingthe measurement light that has passed through the transmissive memberusing a photodetection system placed facing the second surface side ofthe first member.
 16. The exposure method according to claim 12, whereinthe first member has a liquid repellent film formed on the first surfaceof the transmissive member, and the liquid comes into contact with asurface of the liquid repellent film.
 17. The exposure method accordingto claim 12, wherein a surface of the first member with which the liquidcomes into contact is liquid repellent to the liquid.
 18. The exposuremethod according to claim 12, wherein the first member is grounded.